Aerial photograph viewing stereoscope



M r h 1954 .1. BUCKMASTER AERIAL PHOTOGRAPH VIEWING STEREOSCOPE 2 Sheets-Sheet 1 Original Filed Jan.

INVENTOR JA MES L Eva/(MA 571R March 1954 J. BUCKMASTER AERIAL PHOTOGRAPH VIEWING STEREOSCOPE 2 Sheets-Sheet 2 Original Filed Jan. 10, 1945 Q N fl INVENTOR bl f'r ln 6 1 JAMES L. Bum MASTER Patented Mar. 2, 1954 UNITED STATES TENT OFFICE AERIAL PHOTOGRAPH VIEWING STEREOSCOPE James Lloyd Buckmaster, Arlington, Va.

Original application J anu 572,202, now Patent N 24, 1951. v Divided and 6, 1951, Serial No. 214,191

1 Claim. (01. 88-29) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of April 30, 1928 (Ch. 460, 45 Stat. L. 467).

This application is a division of a copending application for a patenton Stereoblique Plotters, Serial No. 572,202, filed January 10, 1945, by

James G. Lewis and myself, for which a Patent No. 25,61,386 was granted on July 24, 1951.

This division relates to stereoscopes and particularly to one for simultaneously viewing two aerial photographs taken of common terrain in directions oblique to the vertical.

In the accompanying drawing:

Figure 1 is a front elevation of my improved stereoscope.

Figure 2 is a side elevation of my stereoscope shown in Figure 1.

Figure 3 is a plan view of my stereoscope in combination with the stereoblique plotter disclosed in the joint application of James G. Lewis and James L. Buckmaster, Serial No. 572,202, filed January 10, 1945, now Patent No. 2,561,386.

Referring to my stereoscope 200 shown in Figures 1, 2, and 3:

A base pedestal 29! is mounted in aligned apertures in an upper photograph support 19 and an intermediate plate 61 by means of a threaded extension into a supporting foot 25 which rests on a base 2|. The pedestal 26! supports a horizontal adjusting arm 202 which is releasably held in adjusted position by a. clamping screw 203. The arm 202 is provided with a terminal clamping collar 204 which in turn supports an adjusting rod 205 when clamped thereto by a clamping screw 226 in the collar 204. The rod 205 is provided with a terminal block 201 which fits between two angle brackets 203 and is held in adjusted position by a clamping screw 209. The two angle brackets 2138 support a plate 2113 to which they are fastened by two screws 2. The plate 2H has a rearwardly extending arm 2I2 which terminates in a balancing weight 213.

Right and left mirrors 2M and 2l5 are secured to the outermost ends of the plate 2l0 by angles 216 and 2H and attaching screws H8. The mirrors 2M and 2l5 are silvered on their under sides instead of on their rear faces to eliminate the passage of light through the glass plates of the mirrors. Right and left hand blocks 2l9 and 22B are pivotally attached to the plate 2w by screws 221, and support eye pieces 222 and 223, each having an adjusting arm identified ary 10, 1945, Serial No. 0. 2,561,386, dated July this application March as 224 and 225, respectively, which are in turn pivotally'attached to the blocks 219 and. 220 by vertical screws 226.

Right and left hand lenses 221 and 228 are mounted on prisms 229 and 230, respectively, while "objective lenses 23! and 232 are on faces of the prisms 229 and 230 which are at right angles to the faces on which the lenses 221 and 228 are mounted. These lenses may be cemented to the prisms 229 and 230 or may be made integral therewith. 7

The prisms 229 and 230 are mounted in housings 233 and 234 which are secured to'th 'under sides of the eye pieces 222 and 223 respectively.

In Figure 3 the stereoscope in combination with the stereo-oblique plotter disclosed in the aforementioned Patent No. 2,561,386 is shown in position over the base 2| upon which a plotting sheet 22 is placed. Oblique photographs 62 and 88 having marginal marks 62a and 80a parallel to the true horizon of the photograph are mounted upon respective supporting plates 6! and 19, and blades or sensing members 83 and M9 of the stereo-oblique plotter are shown in position over the photographs.

On looking through the stereoscope 200 at the two images of a common object, represented by photographs 62 and 82 of Figure 3, the two hairlines 84 and I50 on the blades or sensing members 83 and I49 respectively-appear as a vertical line piercing the earth at some point in the area observed, which point is represented on the map by the position of a drawing element I19. As the drawing element I19 is moved about over the mapping sheet 22, the vertical line is seen to move on the landscape and is used as a pointer to follow features it is desired to map.

S tereoscope adjustment The stereoscope 2B!) is moved forward or backward and turned to the right or left until the mirrors 2M and 2l5 are approximately over the centers of the respective photographs.

The right prism is adjusted by looking to the left edge of the field of view and rotating the right prism 229 in the horizontal plane, by means of the adjusting arm 224 so as to eliminate y parallax in the left side of the field of view. The left prism 230 is similarly adjusted by looking to the right side of the field of view and rotating the left prism 230 by means of the adjusting arm 225 to eliminate y parallax in the right side of the field of view.

These adjustments are repeated, if necessary,

to bring common images on a line parallel to the eye base. The stereoscope is adjusted to suit the eyes of the operator by rotating th prisms 229 and 230 in a vertical plane by means of the arms 22% and 225. The stereoscope is tilted forward or backward by the operator to look from the foreground to the background, by releasing the clamp 209 and rocking the arm 212 to the desired adjustment. After the adjustments described above have been made, a stereoscopic image of each of a succession of points should be obtained which is commensurate with the clearness of the photographs.

It should be understood that the present disclosure is for the purpose of illustration only, and that the invention includes all modifications and equivalents which fall within the spirit and scope of the appended claim.

What I claim is:

In a stereoscope, the combination with a support, two eyepieces, a reflecting prism for one eyepiece arranged to reflect a generally horizontal cone of light rays from one direction into one of said eyepieces, a second reflecting prism for a second of said eyepieces arranged to reflect a generally horizontal beam of light from a direction opposite to that of the cone of light rays directed into said first eyepiece, a support for each prism which permits manual adjustment by rotation on a vertical axis, a hook-shaped adjusting arm coupled to each of said eyepieces for varying the pupillary distance between said eyepieces, a reflecting mirror for bending an upwardly directed cone of light rays from one of two overlapping oblique photographs against the inclined face of the first of said prisms, a second reflecting mirror for bending an upwardly directed cone of light rays from a second of two overlapping oblique photographs, means for supporting said reflecting mirrors in any angular position, an arm supporting a balancing weight for counterbalancing said eyepieces, prisms, and mirrors, an adjustable horizontal arm mounted in said support provided with a terminal clamp, a vertical rod adjustably supported in said clamp and provided with a terminal clamp, and two supporting angle brackets for said eyepiece prism and reflector assembly adiustably supported in said terminal clamp of said vertical rod.

JAMES LLOYD BUCKMASTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,232,606 Ritchie July 10, 1917 1,494,728 Beyerlen May 20, 1924 1,756,062 01st Apr. 29, 1930 1,956,822 Borden May 1, 1934 2,104,552 Blee et al. Jan. 4, 1938 2,229,309 Ryker Jan. 21, 1941 2,229,424 Seeley Jan. 21, 1941 FOREIGN PATENTS Number Country Date 161,607 Switzerland May 15, 1933 

